The present invention relates to a method of mounting an electronic component by applying ultrasonic vibrations.
When a semiconductor chip, which is an example of the electronic component, is mounted on a circuit board by flip chip bonding, bumps of the semiconductor chip are headed for the circuit board, then the bumps, which are made of gold or solder, are respectively bonded to electrodes of the circuit board. A space between the semiconductor chip and the circuit board is filled with synthetic resin so as to protect a circuit face of the semiconductor chip, prevent the bumps from corrosion and improve bonding strength therebetween.
When the semiconductor chip is flip-chip-bonded to the circuit board by applying ultrasonic vibrations, the circuit board is sucked and fixed to a supporting table so as not to displace the circuit board. However, it is very difficult to completely fix the circuit board to the supporting table, so ultrasonic vibrations are transmitted from the semiconductor to the circuit board when a load and ultrasonic vibrations are applied to the semiconductor chip. If the circuit board too is vibrated, relative motion or friction between the semiconductor chip and the circuit board is made small, so that poor bonding therebetween occurs.